Led driving circuit and led apparatus

ABSTRACT

A driving circuit includes: a first connecting port for receiving a first signal during a first operating mode; a second connecting port for receiving a second signal during the first operating mode or receiving a third signal during a second operating mode; a first driving unit coupled to the first connecting port and the second connecting port, for driving an LED element according to the first signal and the second signal during the first operating mode; and a second driving unit coupled to the second connecting port, for driving the LED element according to the third signal during the second operating mode; wherein the second operating mode is different from the first operating mode.

BACKGROUND

Currently, an LED tube may either be plugged into the AC electric powersupply or a power supply system having an inductance ballast. The LEDtube is not adapted to the AC electric power supply, the power supplysystem having an inductance ballast, and the power supply system havingan electrical ballast. Therefore, a fluorescent lamp/tube used in thepower supply system having the electrical ballast may not be directlyreplaced with an LED tube when the fluorescent lamp/tube is burned.Moreover, when an LED tube is applied to the power supply system havingthe inductance ballast, and when the inductance ballast malfunctions,the LED tube also fails to work properly because the failed inductanceballast may block the AC electric power supply from the LED tube.Accordingly, there is a need to provide an LED driver adapted to the ACelectric power supply, the power supply system having an inductanceballast, and the power supply system having an electrical ballast.

SUMMARY

Embodiments of the present invention provide a driving circuit. Thedriving circuit comprises a first connecting port, a second connectingport, a first driving unit, and a second driving unit. The firstconnecting port is arranged for receiving a first signal during a firstoperating mode. The second connecting port is arranged for receiving asecond signal during the first operating mode or receiving a thirdsignal during a second operating mode. The first driving unit is coupledto the first connecting port and the second connecting port, for drivingan LED element according to the first signal and the second signalduring the first operating mode. The second driving unit is coupled tothe second connecting port, for driving the LED element according to thethird signal during the second operating mode. The second operating modeis different from the first operating mode.

In one embodiment, the first connecting port and the second connectingport are arranged to receive a fourth signal and a fifth signal during athird operating mode, the second driving unit is arranged to drive theLED element according to the fourth signal and the fifth signal duringthe third operating mode, and the third operating mode is different fromthe first operating mode and the second operating mode.

In one embodiment, the first driving unit is enabled and the seconddriving unit is disabled during the first operating mode, the firstdriving unit is disabled and the second driving unit is enabled duringthe second operating mode, and the first driving unit is disabled andthe second driving unit is enabled during the third operating mode.

In one embodiment, the first driving unit comprises: a switching controlcircuit, having an input terminal coupled to the first connecting portand an output terminal for generating a control signal; a switchingmodule, having an input terminal coupled to the output terminal of theswitching control circuit, and an output terminal for outputting anoutput signal according to the control signal; and a rectifying andfiltering circuit, coupled to the output terminal of the switchingmodule, for driving the LED element according to the output signalduring the first operating mode.

In one embodiment, the switching module comprises: a relay circuit,configured to have a coil, a moving contact, and a stationary contact;wherein the coil of the relay circuit is coupled to the switchingcontrol circuit, the moving contact of the relay circuit is coupled tothe first connecting port, and the stationary contact of the relaycircuit is coupled to the rectifying and filtering circuit forgenerating the output signal according to the control signal.

In one embodiment, the switching control circuit comprises: atransformer, having a primary coil and a secondary coil, the primarycoil coupled to the first connecting port, and the secondary coilmagnetically coupled to the primary coil; a first rectifier, coupledbetween the secondary coil of the transformer and a ground voltage, forgenerating a first rectifying signal; a voltage converter, coupled tothe first rectifier, having an output terminal for generating aconverting output voltage according to the first rectifying signal; afirst capacitor, coupled to the primary coil of the transformer; asecond capacitor, coupled with the first rectifier in parallel; a thirdcapacitor, coupled between the output terminal of the voltage converterand the ground voltage; and a first Zener diode, coupled with the secondcapacitor in parallel.

In one embodiment, the rectifying and filtering circuit comprises: asecond rectifier, having a first input terminal coupled to the secondconnecting port and the first capacitor and a second input terminalcoupled to the output terminal of the switching module, and having afirst output terminal and a second output terminal for generating asecond rectifying signal to drive the LED element during the firstoperating mode; a second Zener diode, coupled between the first outputterminal and the second output terminal of the second rectifier; and afourth capacitor, coupled between the first output terminal and thesecond output terminal of the second rectifier.

In one embodiment, the second driving unit comprises: a rectifyingcircuit, coupled to the second connecting port, for generating arectifying signal; a filtering circuit, coupled to the rectifyingcircuit, for filtering the rectifying signal to generate a filteringsignal; and a voltage level converting circuit, coupled to the filteringcircuit, for driving the LED element according to the filtering signalduring the second operating mode and the third operating mode; whereinthe rectifying circuit, the filtering circuit, and the voltage levelconverting circuit are connected sequentially.

In one embodiment, the rectifying circuit comprises: a rectifier, havinga first input terminal and a second input terminal coupled to the secondconnecting port, a first output terminal outputting the rectifyingsignal, and a second output terminal coupled to a ground voltage.

In one embodiment, the filtering circuit comprises: an inductor, havinga first terminal coupled to the first output terminal of the rectifierand a second terminal outputting the filtering signal; a resistor,having a first terminal and a second terminal coupled to the firstterminal and the second terminal of the inductor respectively; and acapacitor, having a first terminal coupled to the second terminal of theinductor, and a second terminal coupled to the ground voltage.

In one embodiment, the driving circuit further comprises: a firstfilament simulation circuit, having a first input terminal coupled to afirst terminal of the first connecting port, a second input terminalcoupled to a second terminal of the first connecting port, and an outputterminal coupled to the first driving unit; and a second filamentsimulation circuit, having a first input terminal coupled to a firstterminal of the second connecting port, a second input terminal coupledto a second terminal of the second connecting port, a first outputterminal coupled to the first driving unit and the second driving unit,and a second output terminal coupled to the second driving unit.

In one embodiment, the first filament simulation circuit comprises: afirst resistor, having a first terminal and a second terminal coupled tothe first terminal and the second terminal of the first connecting portrespectively; a first inductor, having a first terminal coupled to thefirst terminal of the first resistor; a second inductor, having a firstterminal coupled to the second terminal of the first resistor; a secondresistor, having a first terminal and a second terminal coupled to asecond terminal of the first inductor and a second terminal of thesecond inductor respectively; and a capacitor, having a first terminaland a second terminal coupled to the second terminal of the firstinductor and the second terminal of the second inductor respectively.

In one embodiment, the driving circuit further comprises: a fuse, havinga first terminal coupled to the first terminal of the first connectingport, and a second terminal coupled to the first terminal of the firstresistor.

In one embodiment, the second filament simulation circuit comprises: afirst inductor, having a first terminal coupled to the first terminal ofthe second connecting port; a second inductor, having a first terminalcoupled to a the second terminal of the second connecting port; acapacitor, having a first terminal and a second terminal coupled to asecond terminal of the first inductor and a second terminal of thesecond inductor respectively; a first resistor, having a first terminalcoupled to the second terminal of the first inductor; and a secondresistor, having a first terminal coupled to a second terminal of thefirst resistor, and a second terminal coupled to the second terminal ofthe second connecting port.

In one embodiment, the driving circuit further comprises: a fuse, havinga first terminal coupled to the first terminal of the first connectingport, and a second terminal coupled to the first terminal of the firstresistor.

Embodiments of the present invention provide a light emitting diode(LED) apparatus. The LED apparatus comprises a first connecting port, asecond connecting port, a first driving unit, and a second driving unit.The first connecting port is arranged to selectively couple to theelectrical ballast or an inductance ballast. The second connecting port,arranged to selectively couple to the electrical ballast, the ACelectric power supply, or the inductance ballast. The first driving unitis coupled to the first connecting port and the second connecting port,for driving an LED element when the first connecting port and the secondport are coupled to the electrical ballast. The second driving unit iscoupled to the second connecting port, for driving the LED element whenthe second connecting port is coupled to the AC electric power supply orwhen the first connecting port and the second connecting port arecoupled to the inductance ballast and the AC electric power supply.

In one embodiment, the first driving unit is enabled and the seconddriving unit is disabled when the first connecting port and the secondport are coupled to the electrical ballast, the first driving unit isdisabled and the second driving unit is enabled when the secondconnecting port is coupled to the AC electric power supply, and thefirst driving unit is disabled and the second driving unit is enabledwhen the first connecting port and the second connecting port arecoupled to the inductance ballast and the AC electric power supply.

In one embodiment, the first driving unit comprises: a switching controlcircuit, having an input terminal coupled to the first connecting portand an output terminal for generating a control signal; a switchingmodule, having an input terminal coupled to input terminal of theswitching control circuit, and an output terminal for outputting anoutput signal according to the control signal; a rectifying andfiltering circuit, coupled to the output terminal of the switchingmodule, for driving the LED element according to the output signalduring the first operating mode.

In one embodiment, the second driving unit comprises: a rectifyingcircuit, coupled to the second connecting port, for generating arectifying signal; a filtering circuit, coupled to the rectifyingcircuit, for filtering the rectifying signal to generate a filteringsignal; and a voltage level converting circuit, coupled to the filteringcircuit, for driving the LED element according to the filtering signalduring the second operating mode and the third operating mode; whereinthe rectifying circuit, the filtering circuit, and the voltage levelconverting circuit are connected sequentially.

In one embodiment, the driving circuit further comprises: a firstfilament simulation circuit, having a first input terminal coupled to afirst terminal of the first connecting port, a second input terminalcoupled to a second terminal of the first connecting port, and an outputterminal coupled to the first driving unit; and a second filamentsimulation circuit, having a first input terminal coupled to a firstterminal of the second connecting port, a second input terminal coupledto a second terminal of the second connecting port, a first outputterminal coupled to the first driving unit and the second driving unit,and a second output terminal coupled to the second driving unit.

BRIEF DESCRIPTION OF THE DRAWINGS

Aspects of the present disclosure are best understood from the followingdetailed description when read with the accompanying figures. It isnoted that, in accordance with the standard practice in the industry,various features are not drawn to scale. In fact, the dimensions of thevarious features may be arbitrarily increased or reduced for clarity ofdiscussion.

FIG. 1 is a diagram illustrating an LED driving circuit in accordancewith some embodiments.

FIG. 2 is a diagram illustrating a first driving unit and a seconddriving unit of the LED driving circuit in accordance with someembodiments.

FIG. 3 is a diagram illustrating a first connecting port, a secondconnecting port, a first fuse, a second fuse, a first filamentsimulation circuit, a second filament simulation circuit, and a firstdriving unit of the LED driving circuit in accordance with someembodiments.

FIG. 4 is a diagram illustrating a second driving unit in accordancewith some embodiments.

FIG. 5 is a diagram illustrating an LED apparatus when a second drivingunit is configured to operate in the first operating mode in accordancewith some embodiments.

FIG. 6 is a diagram illustrating an LED apparatus when a second drivingunit is configured to operate in the second operating mode in accordancewith some embodiments.

FIG. 7 is a diagram illustrating an LED apparatus when a second drivingunit is configured to operate in the third operating mode in accordancewith some embodiments.

DETAILED DESCRIPTION

The following disclosure provides many different embodiments, orexamples, for implementing different features of the provided subjectmatter. Specific examples of components and arrangements are describedbelow to simplify the present disclosure. These are, of course, merelyexamples and are not intended to be limiting. For example, the formationof a first feature over or on a second feature in the description thatfollows may include embodiments in which the first and second featuresare formed in direct contact, and may also include embodiments in whichadditional features may be formed between the first and second features,such that the first and second features may not be in direct contact. Inaddition, the present disclosure may repeat reference numerals and/orletters in the various examples. This repetition is for the purpose ofsimplicity and clarity and does not in itself dictate a relationshipbetween the various embodiments and/or configurations discussed.

Further, spatially relative terms, such as “beneath,” “below,” “lower,”“above,” “upper” and the like, may be used herein for ease ofdescription to describe one element or feature's relationship to anotherelement(s) or feature(s) as illustrated in the figures. The spatiallyrelative terms are intended to encompass different orientations of thedevice in use or operation in addition to the orientation depicted inthe figures. The apparatus may be otherwise oriented (rotated 90 degreesor at other orientations) and the spatially relative descriptors usedherein may likewise be interpreted accordingly.

Notwithstanding that the numerical ranges and parameters setting forththe broad scope of the disclosure are approximations, the numericalvalues set forth in the specific examples are reported as precisely aspossible. Any numerical value, however, inherently contains certainerrors necessarily resulting from the standard deviation found in therespective testing measurements. Also, as used herein, the term “about”generally means within 10%, 5%, 1%, or 0.5% of a given value or range.Alternatively, the term “about” means within an acceptable standarderror of the mean when considered by one of ordinary skill in the art.Other than in the operating/working examples, or unless otherwiseexpressly specified, all of the numerical ranges, amounts, values andpercentages such as those for quantities of materials, durations oftimes, temperatures, operating conditions, ratios of amounts, and thelikes thereof disclosed herein should be understood as modified in allinstances by the term “about.” Accordingly, unless indicated to thecontrary, the numerical parameters set forth in the present disclosureand attached claims are approximations that can vary as desired. At thevery least, each numerical parameter should at least be construed inlight of the number of reported significant digits and by applyingordinary rounding techniques. Ranges can be expressed herein as from oneend point to another end point or between two end points. All rangesdisclosed herein are inclusive of the end points, unless specifiedotherwise.

FIG. 1 is a diagram illustrating an LED driving circuit 100 inaccordance with some embodiments. The LED driving circuit 100 may bearranged to drive an LED element, wherein the LED element may be an LEDtube. According to some embodiments, the LED driving circuit 100 is amultifunctional driving circuit that may be adapted to different powersupply systems. For example, the LED driving circuit 100 may be adaptedto the electrical ballast, the AC electric power supply, and theinductance ballast. FIG. 1 merely shows the main functional blocks ofthe LED driving circuit 100. For brevity, an LED tube 2 is also shown inFIG. 1.

According to some embodiments, the LED driving circuit 100 iselectrically coupled to the LED tube 2 in order to drive the LED tube 2.The LED driving circuit 100 comprises a first connecting port 10, asecond connecting port 20, a first driving unit 30, and a second drivingunit 40. The first driving unit 30 is coupled to the first connectingport 10, the second connecting port 20, and the LED tube 2. The seconddriving unit 40 is coupled to the second connecting port 20 and the LEDtube 2. According to some embodiments, the first connecting port 10 andthe second connecting port 20 may be selectively coupled an electricalballast, an inductance ballast, or AC electric power supply. Dependingon the power supply system, the LED tube 2 may be controlled by thefirst driving unit 30 or the second driving unit 40. Specifically, whenthe first connecting port 10 and the second connecting port 20 arecoupled to an electrical ballast, the first driving unit 30 is arrangedto drive the LED tube 2. When the second connecting port 20 is coupledto the AC electric power supply, the second driving unit 40 is arrangedto drive the LED tube 2. When the first connecting port 10 and thesecond connecting port 20 are coupled to an inductance ballast, thesecond driving unit 40 is arranged to drive the LED tube 2.

Accordingly, depending on the signals received by the first connectingport 10 and the second connecting port 20, one of the first driving unit30 and the second driving unit 40 is arranged to drive the LED tube 2.According to some embodiments, the LED driving circuit 100 may havethree operating modes, i.e. the first operating mode, the secondoperating mode, and the third operating mode. During the first operatingmode, the first connecting port 10 and the second connecting port 20 arecoupled to an electrical ballast for receiving a first signal and asecond signal respectively, and the first driving unit 30 is arranged todrive the LED tube 2 according to the first signal and the secondsignal. During the second operating mode, the second connecting port 20is coupled to the AC electric power supply for receiving a third signal,and the second driving unit 40 is arranged to drive the LED tube 2according to the third signal. During the third operating mode, thefirst connecting port 10 and the second connecting port 20 are coupledto an inductance ballast for receiving a fourth signal and a fifthsignal, and the second driving unit 40 is arranged to drive the LED tube2 according to the fourth signal and the fifth signal. Furthermore, thefirst driving unit 30 may be enabled and the second driving unit 40 maybe disabled during the first operating mode. The first driving unit 30may be disabled and the second driving unit 40 may be enabled during thesecond operating mode. The first driving unit 30 may be disabled and thesecond driving unit 40 may be enabled during the third operating mode.

FIG. 2 is a diagram illustrating the first driving unit 30 and thesecond driving unit 40 of the LED driving circuit 100 in accordance withsome embodiments. For the purpose of description, the first connectingport 10, the second connecting port 20, and the LED tube 2 are alsoshown in FIG. 2. According to some embodiments, the first driving unit30 comprises a switching control circuit 31, a switching module 32, anda rectifying and filtering circuit 33. The switching control circuit 31has an input terminal coupled to the first connecting port 10 and anoutput terminal for generating a control signal Sc according to thesignal on the first connecting port 10. The switching module 32 has afirst input terminal and a second input terminal coupled to the outputterminal of the switching control circuit 32 and the second connectingport 20 respectively, and an output terminal for outputting an outputsignal So according to the control signal Sc and the signal on thesecond connecting port 20. The rectifying and filtering circuit 33 iscoupled to the output terminal of the switching module 32 for generatinga first driving signal Sd1 to drive the LED tube 2 according to theoutput signal So during the first operating mode.

According to some embodiments, the second driving unit 40 comprises arectifying circuit 41, a filtering circuit 42, and a voltage levelconverting circuit 43. The rectifying circuit 41 is coupled to thesecond connecting port 20 for generating a rectifying signal Sraccording to the signal on the second connecting port 20. The filteringcircuit 42 is coupled to the rectifying circuit 41 for filtering therectifying signal Sr to generate a filtering signal Sf. The voltagelevel converting circuit 43 is coupled to the filtering circuit 42 forgenerating a second driving signal Sd2 to drive the LED tube 2 accordingto the filtering signal Sf during the second operating mode and thethird operating mode. Moreover, the rectifying circuit 41, the filteringcircuit 42, and the voltage level converting circuit 43 are connectedsequentially.

Moreover, according to some embodiments, the LED driving circuit 100further comprises a first fuse, a second fuse, a first filamentsimulation circuit, and a second filament simulation circuit. FIG. 3 isa diagram illustrating the first connecting port 10, the secondconnecting port 20, the first fuse F1, the second fuse F2, the firstfilament simulation circuit 50, the second filament simulation circuit60, and the first driving unit 30 of the LED driving circuit 100 inaccordance with some embodiments. For the purpose of description, theLED tube 2 is also shown in FIG. 2.

The first connecting port 10 comprises a first terminal A1 and a secondterminal A2. The second connecting port 20 comprises a first terminal B1and a second terminal B2. The first fuse F1 is coupled between the firstterminal A1 and the first filament simulation circuit 50. The secondfuse F2 is coupled between the first terminal B1 and the second filamentsimulation circuit 60. The first fuse F1 and the second fuse F2 may bethe overcurrent protection devices. When the abnormal large currentflows to the first connecting port 10 and/or the second connecting port20, the first fuse F1 and/or the second fuse F2 may be timely fused oropened to protect the first driving unit 30 and/or the second drivingunit 40.

The first filament simulation circuit 50 has a first input terminalcoupled to the first fuse F1, a second input terminal coupled to thesecond terminal A2 of the first connecting port 10, and an outputterminal coupled to the first driving unit 30. The second filamentsimulation circuit 60 has a first input terminal coupled to the secondfuse F2, a second input terminal coupled to the second terminal B2 ofthe second connecting port 20, a first output terminal coupled to thefirst driving unit 30 and the second driving unit, and a second outputterminal coupled to the second driving unit 40.

The first filament simulation circuit 50 comprises a first resistor R12,a first inductor L4, a second inductor L5, a second resistor R13, and acapacitor C9. The first resistor R12 has a first terminal and a secondterminal coupled to the first terminal A1 (or the first fuse F1) and thesecond terminal A2 of the first connecting port 10 respectively. Thefirst inductor L4 has a first terminal coupled to the first terminal ofthe first resistor R12. The second inductor L5 has a first terminalcoupled to the second terminal of the first resistor R12. The secondresistor R13 has a first terminal and a second terminal coupled to asecond terminal of the first inductor L4 and a second terminal of thesecond inductor L5 respectively. The capacitor C9 has a first terminaland a second terminal coupled to the second terminal of the firstinductor L4 and the second terminal of the second inductor L5respectively.

The second filament simulation circuit 60 comprises a first inductor L6,a second inductor L7, a capacitor C10, a first resistor R14, and asecond resistor R15. The first inductor L6 has a first terminal coupledto the second fuse F2 (or B1), and a second terminal coupled to thefirst driving unit 30 and the second driving unit 40. The secondinductor L7 has a first terminal coupled to the second terminal B2 ofthe second connecting port 20, and a second terminal coupled to thesecond driving unit 40. The capacitor C10 has a first terminal and asecond terminal coupled to the second terminal of the first inductor L6and a second terminal of the second inductor L7 respectively. The firstresistor R14 has a first terminal coupled to the second terminal of thefirst inductor L6. The second resistor R15 has a first terminal coupledto a second terminal of the first resistor R14, and a second terminalcoupled to the second terminal B2 of the second connecting port 20 andthe second driving unit 40.

According to some embodiments, the first filament simulation circuit 50and the second filament simulation circuit 60 are used to simulategeneration of tube Voltage of fluorescent tubes so as to be compatiblewith the electrical/inductance ballasts in the fluorescent tubes andfulfill functions of the electrical/inductance ballasts in detectingtube Voltage, filament resistance, multi stage pre-heating states oftube, multi-stage wattage and the like.

The switching control circuit 31 comprises a transformer T1, a firstrectifier DB1, a voltage converter U1, a first capacitor C1, a secondcapacitor C2, a third capacitor C3, and a Zener diode D1. Thetransformer T1 has a primary coil and a secondary coil, the primary coilhas a first terminal coupled to the second terminal of the inductor L4,and the secondary coil is magnetically coupled to the primary coil. Thefirst rectifier DB1 comprises four diodes connected in a circle. Thefirst rectifier DB1 has a first terminal coupled to a first terminal ofthe secondary coil of the transformer T1, a second terminal coupled to asecond terminal of the secondary coil of the transformer T1, a thirdterminal coupled to the ground voltage, and a fourth terminal generatinga first rectifying signal Sr1.

The voltage converter U1 is coupled to the first rectifier DB1, and thevoltage converter U1 has an output terminal for generating a convertingoutput voltage (i.e. the control signal Sc) according to the firstrectifying signal Sr1. The first capacitor C1 has a first terminalcoupled to a second terminal of the primary coil of the transformer T1,and a second terminal coupled to the rectifying and filtering circuit33. The second capacitor C2 has a first terminal coupled to the fourthterminal of the first rectifier DB1, and a second terminal coupled tothe ground voltage, i.e. the second capacitor C2 and the first rectifierDB1 is connected in parallel. The third capacitor C3 has a firstterminal coupled the output terminal of the voltage converter U1, and asecond terminal coupled to the ground voltage. The Zener diode D1 has afirst terminal coupled to the fourth terminal of the first rectifier DB1and a second terminal coupled to the ground voltage, i.e. the Zenerdiode D1 and the second capacitor C2 are connected in parallel.

The switching module 32 comprises a relay circuit K1. The relay circuitK1 is configured to have a coil 32 a, a moving contact Ta, and astationary contact Tb. The coil 32 a of the relay circuit K1 is coupledto the switching control circuit 31, the moving contact Ta of the relaycircuit K1 is coupled to the first terminal of the first primary coil ofthe transformer T1, and the stationary contact Tb of the relay circuitK1 is coupled to the rectifying and filtering circuit 33 for generatingthe output signal So according to the control signal Sc. When the firstconnecting port 10 is coupled to an electrical ballast, the currentflows to the coil 32 a of the relay circuit K1 from the switchingcontrol circuit 31, and the relay circuit K1 is conducted such that therectifying and filtering circuit 33 is conducted to drive the LED tube2. In another embodiment, the switching module 32 may be a triode, acontrollable electronic switch, or a switching module formed by thecontrollable electronic switches.

The rectifying and filtering circuit 33 comprises a second rectifierDB2, a Zener diode D2, and a capacitor C4. The second rectifier DB2comprises four diodes connected in a circle. The second rectifier DB2has a first terminal coupled a second terminal of the capacitor C1 andthe second terminal of the inductor L6, a second terminal coupled to therelay circuit K1 for receiving the output signal So, a third terminalgenerating a second rectifying signal (i.e. Sd1) for driving the LEDtube 2 during the first operating mode, and a fourth terminal coupled tothe ground voltage. The Zener diode D2 has a first terminal coupled tothe third terminal of the second rectifier DB2, and a second terminalcoupled to the ground voltage. The capacitor C4 has a first terminalcoupled to the third terminal of the second rectifier DB2, and a secondterminal coupled to the ground voltage.

FIG. 4 is a diagram illustrating the second driving unit 40 inaccordance with some embodiments. The second driving unit 40 comprisesthe rectifying circuit 41, the filtering circuit 42, and the voltagelevel converting circuit 43. The rectifying circuit 41 comprises arectifier DB3. The rectifier DB3 comprises four diodes connected in acircle. The rectifier DB3 has a first terminal coupled to the secondterminal of the inductor L6, a second terminal coupled to the secondterminal of the inductor L7, a third terminal outputting the rectifyingsignal Sc, and a fourth terminal coupled to the ground voltage.

The filtering circuit 42 comprises an inductor L1, a resistor R1, and acapacitor C5. The inductor L1 has a first terminal coupled to the thirdterminal of the rectifier DB3 and a second terminal outputting thefiltering signal Sf. The resistor R1 has a first terminal and a secondterminal coupled to the first terminal and the second terminal of theinductor L1 respectively. The capacitor C5 has a first terminal coupledto the second terminal of the inductor L1, and a second terminal coupledto the ground voltage.

The voltage level converting circuit 43 comprises a pulse-widthmodulator (PWM) U2, a plurality of resistors R3, R4, R5, R6, R7, R8, R9,R10, R11, a plurality of capacitors C6, C7, C8, a plurality of inductorsL2, L3, and a plurality of diodes D3, D4. The voltage level convertingcircuit 43 may be configured to be a Buck converter, a Boost converter,or a Buck-Boost converter. The pulse-width modulator U2 has eight pins.The resistors R3 and R4 are serially connected between the secondterminal of the inductor L1 and the first pin (i.e. the number 1 in thepulse-width modulator U2) of the pulse-width modulator U2. The capacitorC7 is coupled between the first pin and the ground voltage. The resistorR6 has a first terminal coupled to the first pin, and a second terminalcoupled to the cathode of the diode D4. The inductor L3 is coupledbetween the anode of the diode D4 and the ground voltage. The resistorsR7 and R8 are serially connected between the anode of the diode D4 andthe ground voltage. The second pin (i.e. the number 2 in the pulse-widthmodulator U2) of the pulse-width modulator U2 is coupled to theconnecting node of the resistors R7 and R8. The resistor R9 and thecapacitor C8 are serially connected between the third pin (i.e. thenumber 3 in the pulse-width modulator U2) of the pulse-width modulatorU2 and the ground voltage. The fourth pin (i.e. the number 4 in thepulse-width modulator U2) and the fifth pin (i.e. the number 5 in thepulse-width modulator U2) of the pulse-width modulator U2 is coupled tothe ground voltage. The resistors R10 and R11 are coupled between thesixth pin (i.e. the number 6 in the pulse-width modulator U2) of thepulse-width modulator and the ground voltage. The anode of the diode D3is coupled to the seventh pin (i.e. the number 7 in the pulse-widthmodulator U2) and the eighth pin (i.e. the number 8 in the pulse-widthmodulator U2) of the pulse-width modulator U2. The cathode of the diodeD3 is coupled to the anode (i.e. LED+) of the LED tube 2. A firstterminal of the inductor L2 is coupled to the anode of the diode D3. Thecapacitor C6 has a first terminal coupled to a second terminal of theinductor L2, and a second terminal coupled to the cathode of the diodeD3. The resistor R5 has a first terminal and a second terminal coupledto the first terminal and the second terminal of the capacitor C6respectively. According to the embodiment, the second driving signal Sd2is generated on the terminals LED+ and LED-, wherein the terminals LED+and LED− are coupled to the anode and the cathode of the LED tube 2respectively.

In practice, the operating modes of the LED driving circuit 100 maycorrespond to different connections of the first connecting port 10 andthe second connecting port 20.

FIG. 5 is a diagram illustrating an LED apparatus 500 when the seconddriving unit 100 is configured to operate in the first operating mode inaccordance with some embodiments. The LED apparatus 500 is an LEDillumination system. The LED apparatus 500 comprises an electricalballast 3, the LED driving circuit 100, and the LED tube 2. Theelectrical ballast 3 comprises two connecting pins L and N on one sideand four connecting pins A11, A12, B11, and B12 on the other side. Theconnecting pin L may be the hot wire, and the connecting pin N may bethe neutral wire. The connecting pins L and N are coupled to the ACelectric power supply, e.g. the AC electric power supply may be 110V ACpower or 220 V AC power. The connecting pins A11 and A12 are coupled tothe first terminal A1 and the second terminal A2 of the first connectingport 10 respectively. The connecting pins B11 and B12 are coupled to thefirst terminal B1 and the second terminal B2 of the second connectingport 20 respectively. During the first operating mode, the LED drivingcircuit 100 receives the first input signal and the second input signalgenerated by the electrical ballast 3 on the terminals A1, A2 and B1, B2respectively. The electrical ballast 3 is arranged to generate the firstinput signal and the second input signal by limiting the amount ofcurrent of the AC electric power supply.

Please refer to FIG. 3 again, during the first operating mode, after thefirst filament simulation circuit 50 is pre-heated, the first inputsignal on the first terminal A1 and the second terminal A2 is passed tothe switching control circuit 31 via the first filament simulationcircuit 50. The switching control circuit 31 generates the controlsignal Sc according to the first input signal. The control signal Sc maybe regarded as the supply power of the switching module 32. When theswitching module 32 is conducted by electric, the switching module 32may turn on the switch in the relay circuit K1 to generate the outputsignal So to the rectifying and filtering circuit 33. Then, therectifying and filtering circuit 33 is conducted. Meanwhile, after thesecond filament simulation circuit 60 is pre-heated, the second inputsignal on the first terminal B1 and the second terminal B2 is passed tothe rectifying and filtering circuit 33 via the second filamentsimulation circuit 60. Then, the rectifying and filtering circuit 33 isarranged to rectify and filter the signals received from the switchingmodule 32 and the second filament simulation circuit 60 to generate thefirst driving signal Sd1 for driving the LED tube 2. According to someembodiments, a control circuit (not shown) may be arranged to disablethe second driving unit 40 during the first operating mode.

FIG. 6 is a diagram illustrating an LED apparatus 600 when the seconddriving unit 100 is configured to operate in the second operating modein accordance with some embodiments. The LED apparatus 600 is an LEDillumination system. During the second operating mode, the firstterminal B1 and the second terminal B2 of the second connecting port 20of the second driving unit 100 is coupled to the connecting pins L and Nrespectively, and the connecting pins L and N are coupled to the ACelectric power supply, e.g. the AC electric power supply may be 110V ACpower or 220 V AC power. The first terminal A1 and the second terminalA2 of the first connecting port 10 of the second driving unit 100 arekept floating during the second operating mode.

Please refer to FIG. 3 and FIG. 4 again, during the second operatingmode, the AC electric power supply on the first terminal B1 and thesecond terminal B2 is passed to the rectifying circuit 41 via the secondfilament simulation circuit 60. The rectifying circuit 41 generates therectifying signal Sr according to the AC electric power supply. Then,the filtering circuit 42 is arranged to filter out the rectifying signalSr to generate the filtering signal Sf. Then, the voltage levelconverting circuit 43 is arranged to generate the second driving signalSd2 with constant current for driving the LED tube 2. According to someembodiments, a control circuit (not shown) may be arranged to disablethe first driving unit 30 during the second operating mode.

FIG. 7 is a diagram illustrating an LED apparatus 700 when the seconddriving unit 100 is configured to operate in the third operating mode inaccordance with some embodiments. The LED apparatus 600 is an LEDillumination system. The LED apparatus 700 comprises an inductanceballast 4, the second driving unit 100, and a starter 5. The inductanceballast 4 comprises a first terminal coupled to the connecting pin L anda second terminal coupled to the first terminal A1 of the firstconnecting port 10. The starter may be an LED starter. The starter 5comprises a first terminal coupled to the second terminal B2 of thesecond connecting port 20 and a second terminal coupled to the secondterminal A2 of the first connecting port 10. The first terminal B1 ofthe second connecting port 20 is coupled to the connecting pin N. Theconnecting pins L and N are coupled to the AC electric power supply,e.g. the AC electric power supply may be 110V AC power or 220 V ACpower.

Please refer to FIG. 3 and FIG. 4 again, during the third operatingmode, the input terminal of the first terminal B1 and the secondterminal B2 is the industrial-frequency signal. The inductive ballast 4is arranged to generate the industrial-frequency signal by limiting theamount of current of the AC electric power supply. Theindustrial-frequency signal flows to the resistor R12 of the firstfilament simulation circuit 50. As the resistance of the resistor R12 isrelatively low, most of the current of the industrial-frequency signalpasses through the resistor R12 to reach the starter 5. The outputsignal of the starter 5 and the signal on the connecting pin N arereceived by the terminal B2 and B1 of the second connecting port 20. Thereceived signal on the first terminal B1 and the second terminal B2 ispassed to the rectifying circuit 41 via the second filament simulationcircuit 60. The rectifying circuit 41 generates the rectifying signal Sraccording to the received signal. Then, the filtering circuit 42 isarranged to filter out the rectifying signal Sr to generate thefiltering signal Sf. Then, the voltage level converting circuit 43 isarranged to generate the second driving signal Sd2 with constant currentfor driving the LED tube 2. According to some embodiments, a controlcircuit (not shown) may be arranged to disable the first driving unit 30during the third operating mode.

The foregoing outlines features of several embodiments so that thoseskilled in the art may better understand the aspects of the presentdisclosure. Those skilled in the art should appreciate that they mayreadily use the present disclosure as a basis for designing or modifyingother processes and structures for carrying out the same purposes and/orachieving the same advantages of the embodiments introduced herein.Those skilled in the art should also realize that such equivalentconstructions do not depart from the spirit and scope of the presentdisclosure, and that they may make various changes, substitutions, andalterations herein without departing from the spirit and scope of thepresent disclosure.

Moreover, the scope of the present application is not intended to belimited to the particular embodiments of the process, machine,manufacture, composition of matter, means, methods and steps describedin the specification. As one of ordinary skill in the art will readilyappreciate from the disclosure of the present invention, processes,machines, manufacture, compositions of matter, means, methods, or steps,presently existing or later to be developed, that perform substantiallythe same function or achieve substantially the same result as thecorresponding embodiments described herein may be utilized according tothe present invention. Accordingly, the appended claims are intended toinclude within their scope such processes, machines, manufacture,compositions of matter, means, methods, or steps.

1. A driving circuit, comprising: a first connecting port, arranged toreceive a first signal during a first operating mode; a secondconnecting port, arranged to receive a second signal during the firstoperating mode or receiving a third signal during a second operatingmode; a first driving unit, coupled to the first connecting port and thesecond connecting port, for driving an LED element according to thefirst signal and the second signal during the first operating mode; anda second driving unit, coupled to the second connecting port, fordriving the LED element according to the third signal during the secondoperating mode; wherein the second operating mode is different from thefirst operating mode, wherein the first connecting port and the secondconnecting port are arranged to receive a fourth signal and a fifthsignal during a third operating mode, the second driving unit isarranged to drive the LED element according to the fourth signal and thefifth signal during the third operating mode, and the third operatingmode is different from the first operating mode and the second operatingmode.
 2. (canceled)
 3. The driving circuit of claim 1, wherein the firstdriving unit is enabled and the second driving unit is disabled duringthe first operating mode, the first driving unit is disabled and thesecond driving unit is enabled during the second operating mode, and thefirst driving unit is disabled and the second driving unit is enabledduring the third operating mode.
 4. The driving circuit of claim 1,wherein the first driving unit comprises: a switching control circuit,having an input terminal coupled to the first connecting port and anoutput terminal for generating a control signal; a switching module,having an input terminal coupled to the output terminal of the switchingcontrol circuit, and an output terminal for outputting an output signalaccording to the control signal; a rectifying and filtering circuit,coupled to the output terminal of the switching module, for driving theLED element according to the output signal during the first operatingmode.
 5. The driving circuit of claim 4, wherein the switching modulecomprises: a relay circuit, configured to have a coil, a moving contact,and a stationary contact; wherein the coil of the relay circuit iscoupled to the switching control circuit, the moving contact of therelay circuit is coupled to the first connecting port, and thestationary contact of the relay circuit is coupled to the rectifying andfiltering circuit for generating the output signal according to thecontrol signal.
 6. The driving circuit of claim 4, wherein the switchingcontrol circuit comprises: a transformer, having a primary coil and asecondary coil, the primary coil coupled to the first connecting port,and the secondary coil magnetically coupled to the primary coil; a firstrectifier, coupled between the secondary coil of the transformer and aground voltage, for generating a first rectifying signal; a voltageconverter, coupled to the first rectifier, having an output terminal forgenerating a converting output voltage according to the first rectifyingsignal; a first capacitor, coupled to the primary coil of thetransformer; a second capacitor, coupled with the first rectifier inparallel; a third capacitor, coupled between the output terminal of thevoltage converter and the ground voltage; and a first Zener diode,coupled with the second capacitor in parallel.
 7. The driving circuit ofclaim 6, wherein the rectifying and filtering circuit comprises: asecond rectifier, having a first input terminal coupled to the secondconnecting port and the first capacitor and a second input terminalcoupled to the output terminal of the switching module, and having afirst output terminal and a second output terminal for generating asecond rectifying signal to drive the LED element during the firstoperating mode; a second Zener diode, coupled between the first outputterminal and the second output terminal of the second rectifier; and afourth capacitor, coupled between the first output terminal and thesecond output terminal of the second rectifier.
 8. The driving circuitof claim 1, wherein the second driving unit comprises: a rectifyingcircuit, coupled to the second connecting port, for generating arectifying signal; a filtering circuit, coupled to the rectifyingcircuit, for filtering the rectifying signal to generate a filteringsignal; and a voltage level converting circuit, coupled to the filteringcircuit, for driving the LED element according to the filtering signalduring the second operating mode and a third operating mode; wherein therectifying circuit, the filtering circuit, and the voltage levelconverting circuit are connected sequentially.
 9. The driving circuit ofclaim 8, wherein the rectifying circuit comprises: a rectifier, having afirst input terminal and a second input terminal coupled to the secondconnecting port, a first output terminal outputting the rectifyingsignal, and a second output terminal coupled to a ground voltage. 10.The driving circuit of claim 8, wherein the filtering circuit comprises:an inductor, having a first terminal coupled to the first outputterminal of the rectifier and a second terminal outputting the filteringsignal; a resistor, having a first terminal and a second terminalcoupled to the first terminal and the second terminal of the inductorrespectively; and a capacitor, having a first terminal coupled to thesecond terminal of the inductor, and a second terminal coupled to theground voltage.
 11. The driving circuit of claim 1, further comprising:a first filament simulation circuit, having a first input terminalcoupled to a first terminal of the first connecting port, a second inputterminal coupled to a second terminal of the first connecting port, andan output terminal coupled to the first driving unit; and a secondfilament simulation circuit, having a first input terminal coupled to afirst terminal of the second connecting port, a second input terminalcoupled to a second terminal of the second connecting port, a firstoutput terminal coupled to the first driving unit and the second drivingunit, and a second output terminal coupled to the second driving unit.12. The driving circuit of claim 11, wherein the first filamentsimulation circuit comprises: a first resistor, having a first terminaland a second terminal coupled to the first terminal and the secondterminal of the first connecting port respectively; a first inductor,having a first terminal coupled to the first terminal of the firstresistor; a second inductor, having a first terminal coupled to thesecond terminal of the first resistor; a second resistor, having a firstterminal and a second terminal coupled to a second terminal of the firstinductor and a second terminal of the second inductor respectively; anda capacitor, having a first terminal and a second terminal coupled tothe second terminal of the first inductor and the second terminal of thesecond inductor respectively.
 13. The driving circuit of claim 12,further comprising: a fuse, having a first terminal coupled to the firstterminal of the first connecting port, and a second terminal coupled tothe first terminal of the first resistor.
 14. The driving circuit ofclaim 11, wherein the second filament simulation circuit comprises: afirst inductor, having a first terminal coupled to the first terminal ofthe second connecting port; a second inductor, having a first terminalcoupled to the second terminal of the second connecting port; acapacitor, having a first terminal and a second terminal coupled to asecond terminal of the first inductor and a second terminal of thesecond inductor respectively; a first resistor, having a first terminalcoupled to the second terminal of the first inductor; and a secondresistor, having a first terminal coupled to a second terminal of thefirst resistor, and a second terminal coupled to the second terminal ofthe second connecting port.
 15. The driving circuit of claim 14, furthercomprising: a fuse, having a first terminal coupled to the firstterminal of the first connecting port, and a second terminal coupled tothe first terminal of the first resistor.
 16. A light emitting diode(LED) apparatus, comprising: a first connecting port, arranged toselectively couple to the electrical ballast or an inductance ballast; asecond connecting port, arranged to selectively couple to the electricalballast, an AC electric power supply, or the inductance ballast; a firstdriving unit, coupled to the first connecting port and the secondconnecting port, for driving an LED element when the first connectingport and the second connecting port are coupled to the electricalballast; and a second driving unit, coupled to the second connectingport, for driving the LED element when the second connecting port iscoupled to the AC electric power supply or when the first connectingport and the second connecting port are coupled to the inductanceballast and the AC electric power supply, wherein the first driving unitis enabled and the second driving unit is disabled when the firstconnecting port and the second connecting port are coupled to theelectrical ballast, the first driving unit is disabled and the seconddriving unit is enabled when the second connecting port is coupled tothe AC electric power supply, and the first driving unit is disabled andthe second driving unit is enabled when the first connecting port andthe second connecting port are coupled to the inductance ballast and theAC electric power supply.
 17. (canceled)
 18. The LED apparatus of claim16, wherein the first driving unit comprises: a switching controlcircuit, having an input terminal coupled to the first connecting portand an output terminal for generating a control signal; a switchingmodule, having an input terminal coupled to input terminal of theswitching control circuit, and an output terminal for outputting anoutput signal according to the control signal; a rectifying andfiltering circuit, coupled to the output terminal of the switchingmodule, for driving the LED element according to the output signalduring the first operating mode.
 19. The LED apparatus of claim 16,wherein the second driving unit comprises: a rectifying circuit, coupledto the second connecting port, for generating a rectifying signal; afiltering circuit, coupled to the rectifying circuit, for filtering therectifying signal to generate a filtering signal; and a voltage levelconverting circuit, coupled to the filtering circuit, for driving theLED element according to the filtering signal during the secondoperating mode and the third operating mode; wherein the rectifyingcircuit, the filtering circuit, and the voltage level converting circuitare connected sequentially.
 20. The LED apparatus of claim 16, furthercomprising: a first filament simulation circuit, having a first inputterminal coupled to a first terminal of the first connecting port, asecond input terminal coupled to a second terminal of the firstconnecting port, and an output terminal coupled to the first drivingunit; and a second filament simulation circuit, having a first inputterminal coupled to a first terminal of the second connecting port, asecond input terminal coupled to a second terminal of the secondconnecting port, a first output terminal coupled to the first drivingunit and the second driving unit, and a second output terminal coupledto the second driving unit.